2-氨基苯硫酚NIR-SERS光谱及其在纳米银表面吸附行为分析

摘要

Two-dimensional nano scale silver films were prepared using the electrostatic self-assembled method in this paper.UV-vis adsorption spectrum of the silver nanofilm shows that the plasmonic resonance band is in the region of 400～900 nm,which extends to the near infrared region.This plasmonic resonance band is able to be matched with the 785 nm excitation source.With 2-ATP used as the tested molecules,we have obtained the near infrared surface-enhanced Raman scattering (NIR-SERS) spectra of 2-ATP adsorbed on the silver nanofilm with good spectral reproducibility.Meanwhile,the enhancement factor (EF) of this silver nanofilm was evaluated using the tested molecule of 2-ATP,and the EF is up to ～2.19 × 109.The geometry optimization and calculated wavenumbers of 2-ATP and 2-ATP-Ag are performed with DFT,B3LYP functional,and the 6-31G/LanL2DZ basis set.The calculated wavenumbers match well with the experimental data.In addition,the adsorption behavior of the 2-ATP molecule adsorbed on the surface of silver nanoparticle was also analyzed and found that the 2-ATP molecule adsorbed on the surface of silver through the group of--SH.Meanwhile,the-SH group will be oxidized by Ag nanoparticles when 2-ATP molecules adsorbed on the surface of silver.%本文采用静电自组装的方法制备了二维纳米银膜.UV-vis吸收光谱显示其等离子体共振吸收带位于400～900 nm的光谱范围,延伸到了近红外区,可以较好的匹配785 nm的近红外激发光源.以该纳米银膜为基底,对2-氨基苯硫酚(2-ATP)分子进行了近红外表面增强拉曼散射(NIR-SERS)检测,获得了重复性良好的NIR-SERS光谱图.实验表明:以2-ATP为探针分子时,该纳米银膜的NIR-SERS增强因子达到2.19×109.同时,本文采用密度泛函理论(DFT),以B3LYP/6-31G为基函数,对2-ATP分子进行结构优化和普通拉曼光谱(NR)计算,发现理论值和实验值吻合较好.此外,对2-ATP的NIR-SERS谱带进行了归属分析,发现当2-ATP分子在纳米银表面吸附时,是以-SH基团吸附到银表面,且同时-SH基团会被纳米银氧化.